Rolling ball assembly and deck

ABSTRACT

A rolling ball assembly for a rolling ball deck with a spherical ball (10), a support for the ball to permit free rotation about any horizontal axis through the ball; a pair of horizontal drive shafts (4, 5), one on either sie of the ball; a collar (8, 9) on each driving shaft, with the periphery of each collar being in driving engagement with the ball at or close to a horizontal plane through the equator of the ball, and between the horizontal axis of the ball perpendicular to the drive shafts and the horizontal axis parallel to the drive shafts so the ball may be rotated about any horizontal axis through rotation of the drive shafts.

The present invention relates to a rolling ball assembly for a rollingball deck, and also to a deck incorporating a plurality of rolling ballassemblies.

Rolling ball decks having a plurality of steel balls supported to befully rotatable are well known and widely used to assist in theconveyance of articles in warehouses, etc. It is also known to providerolling ball decks with the balls driven to rotation in one particulardirection, and proposals have been made for omni-directionallyrotatable, driven ball decks but these have been complex in constructionand consequently expensive to manufacture. One proposal for providing asingle, driven rolling ball is to be found in GB-A-1366206, where twoperpendicular drive rollers in contact with the driven ball are spacedapart by 90° about the ball for rotating the ball in mutuallyperpendicular directions.

The present invention seeks to provide a simple, and thereforerelatively cheap, driven rolling ball assembly for a rolling ball deck.

According to the invention there is provided a rolling ball assembly forrolling ball deck, comprising a spherical ball, means for supporting theball for free rotation about any horizontal axis through the ball; apair of horizontal drive shafts, one either side of the ball; a collaron each driving shaft and a periphery of each collar being in drivingengagement with the ball at or close to a horizontal plane through theequator of the ball, and between the horizontal axis of the ballperpendicular to the drive shafts and the horizontal axis parallel tothe drive shafts whereby by rotating the drive shafts the ball may berotated about any horizontal axis.

According to another aspect, the invention provides a rolling ball deckcomprising a plurality of rolling ball assemblies as set out above.

Preferred embodiments of the invention will now be described, by way ofexample only, with reference to the accompanying drawings, wherein:

FIG. 1 is a side-elevation through a rolling ball deck showing anindividual rolling ball assembly;

FIG. 2 is a plan view of the rolling ball assembly of FIG. 1,

FIG. 3 is an isometric view of alternative rolling ball assembly usingconical collars,

FIGS. 3a to 3d show schematically in plan and elevation, a rolling ballassembly in use depicting modes of operation,

FIG. 4 is a sectional view of a rolling ball deck incorporatingpreferred supporting blocks, overload protection and connection to drivemeans,

FIG. 4a is a plan view of FIG. 4 with ball deck cover removed,

FIG. 5 is an enlarged partial view taken from FIG. 4 showing a resilientmaterial protective cap arrangement,

FIG. 6 is a view corresponding to FIG. 5 but showing an alternativemetal protective cap, and

FIG. 7 shows a more preferred protective cap.

Referring to FIGS. 1 and 2, an individual rolling ball assembly, formingpart of a multiple ball assembly rolling ball deck, generally comprisesa base plate 1, a rolling bearing 2, shown as a ball unit, mounted on aninclined face of a flange 3 which projects from the base plate 1, andother components as follows. A pair of parallel drive shafts 4, 5, arerotatably supported in respective brackets 6, 7, which project from thebase plate 1. Each drive shaft has an annular collar 8, 9, affixed forrotation therewith, and a driven spherical ball 10 supported on the ballunit 2 between the drive shafts 4, 5, and resting against a corner 8a,9a, of each of the annular collars 8, 9. An apertured cover plate 11 ispositioned over the rolling assembly so that each driven spherical ball10 has a small clearance from the aperture in the plate and projectsfreely therethrough to a small distance above the surface of the plate11.

The rolling bearing 2 is a conventional ball-type rolling bearing orunit with a rolling ball supported in a part spherical bearing. Anyfunctionally similar bearing could be used. The rolling bearing 2 is letin to the inclined face of flange 3. The drive shafts 4, 5, extend to aseries of side-by-side rolling ball assemblies in the deck (not shownbut see FIGS. 4 and 4a) for simultaneously driving them, and each isconnected to a suitable bi-directional drive mechanism, for example anelectric motor, through e.g. a belt or chain drive or similar linkage.In the ball deck, all equivalent drive shafts 4 may be connected to onebi-directional drive mechanism (not shown) and equivalent drive shafts 5to another, single bi-directional drive mechanism.

The collars (8, 9) are mounted on the shafts in any suitable manner, forexample by keying or means of cooperating polygonal section on thesurface of the shafts and the inside surface of the annular collars (8,9); generally any manner of securement enables the collars to rotatewith the shafts will do. The collars could be formed as integral partsof the drive shafts and may take forms, other than the annular collarsshown e.g. conical (as shown in FIG. 3). The annular collars 8, 9, canbe generally plain cylindrical, with each corner 8a, 9a, in drivingengagement with the spherical ball 10 having a small radius to spreadthe contact load in use over a greater surface area of the driven ball10.

The drive ball 10 is supported on the rolling bearing 2 offset from thevertical axis of the ball and in a vertical plane B parallel to andequidistant from the axes of the parallel drive shafts, so that the ballrests against the corners 8a, 9a of the collars 8, 9, and the annularcollars engage the driven ball symmetrically about that plane, and atpoints at or near (just below) the equator E of the driven ball. Thecontact area between the driven ball and each annular collar is small.The collars are shown contacting the driven ball 10 at points part waybetween the horizontal axes through the ball, parallel and perpendicularto the drive shafts, and those axes represent the limits between whichthe points of contact should be. As shown each point of contact is at apoint on or just below the equator E of the driven ball substantiallyequidistant from the plane B defined above and plane C perpendicular tothe plane B through the vertical axis A of the ball. This sets spinradii, x, y, through which the driven ball is rotated by the respectivecollar, to be equal to one another.

All parts are of metal with the collars being hardened steel and thedriven ball steel. Other materials could be used, e.g. a spherical ball10 of hard plastics material, could be used.

FIG. 3 shows a ball unit wherein the driven ball 10 is supported by arolling ball bearing 2 rotatably mounted upon a substantially solidblock 3a rigidly affixed to the base plate 1, and supported by surfaceparts of conical collars 8b and 9b. Drive shafts 4, 5 are supported inmountings 7 rigidly secured to the base plate.

The operation of an individual rolling ball assembly will now bedescribed, with reference to FIGS. 3a to 3d. Generally, the driven ball10 is rotated about a horizontal axis through the centre of the ball, byclockwise CW and/or anticlockwise ACW rotation of the drive shaft(s) 4and/or 5. The drive is imparted to the driven ball at the singlepoint(s) of contact of each of the collars 8, 9 and the ball 10. Thedirection of rotation of the driven ball is determined by the speed anddirection of rotation of the drive shaft(s) and will be explained indetail with reference to the four cases represented by FIGS. 3a, b, c,and d.

In FIG. 3a both shafts are rotated in the same direction (clockwise CW)at the same speed so that the ball is rotated in one direction (feed tothe left) about a horizontal axis parallel to axes of the drive shafts,while in FIG. 3b both shafts are rotated in the opposite direction(anti-clockwise ACW) and the driven ball rotated about the samehorizontal axis but in the opposite direction (feed to the right).

In FIG. 3c the left hand drive shaft is rotated in an anti-clockwisedirection ACW and the right hand shaft in the clockwise CW direction,and the product of the rotational forces on the ball causes the ball torotate in one direction (forward feed) about a horizontal axisperpendicular to the axes of the drive shafts. In FIG. 3d the shafts arerotated oppositely to the rotation shown in FIG. 3c, i.e. the left handclockwise CW and the right hand anti-clockwise ACW, and the ball isrotated about the same horizontal axis but in the opposite direction(backward feed). In both the case of FIGS. 3c and d where the shafts arecounter-rotated, the speeds of rotation are kept the same to achieve theresult shown, but by varying the relative speeds of rotation thedirection of rotation can be varied between the limit conditionsillustrated. By stopping one shaft and rotating only the other, thedriven ball can be rotated in directions at 45° to the axes of the driveshaft.

Referring to FIGS. 4 and 4a of the drawings there are shown preferredmodications to the supporting structure and the ball unit 2, to simplifyand possibly strengthen the construction and to provide protectionagainst overloading. This arrangement provides a "driven-over" facilityenabling depression of the spherical balls 10 and of the ball bearings 2upon application of an overload, e.g. a vehicle wheel and thereafterpermit return of these items to normal, operational position in theabsence of overload. The arrangement comprises a spring loaded ball unitassembly 11a, capable of displacement in a vertical plane through thecentre of rotation of said ball unit. The ball unit 2 is supported in aninclined face 3 of one web of an integrally formed mounting block 15,supporting the drive shafts 4,5 in webs 7 thereof.

Within a cylindrical aperture 13 in web 3 a spring cup 13 includesdisc-type springs 12. The ball bearing 2 projects above a flange on itshousing 11a. The ball unit 2 and housing can be displaced as a unit onthe axis 14 within the cup 13 when sufficient (over-) load is applied tothe spherical ball 10 to overcome predetermined tension in the discsprings 12. Deflection of the spherical ball 10 is limited by a stopmember in the form of supporting plate 16 bolted at 17 to rest on aledge of the block 15. Thus when the ball 10 is overloaded, it will reston the stop member 16 the ball unit 2 and associated housing 11a beingcorrespondingly deflected in the cup 13 such that damage thereto isminimised or avoided.

FIGS. 4 and 4a also show an arrangement of protective cap 18, 19, 20 tobe described subsequently with reference to FIG. 5. The collars 8, 9 areshown pinned at 21 to the shaft 5 which has a hexagonal cross-section toengage corresponding hexagonal bores in the collars. Shaft 4 is shownconnected for bi-directional drive to a driving shaft 22 through gearing21b keyed to the respective shafts at 21a. Similar driving provision ismade for the other shaft. Said driving shaft 22 projects beyond an endof the assembly to be supported within a bearing 23 and having at itsremote end a pulley 24 for connection to an appropriate bi-directionaldrive system (not shown). One-piece blocks 15 are conveniently bolted at15a to the base plate 1 and a series thereof spaced along said baseplate in longitudinal and lateral rows. In normal load transporting use,the strength of springs 12 will be such that the spherical balls retaintheir position as shown in FIG. 4 to deflect only in an overloadsituation.

Referring to FIG. 5 of the drawings a protective cap of a resilientlyflexible plastics or elastomeric material 18 has an upper surface part20 extending between a surface part of the ball 10, over the aperture inthe top plate 11 and over a peripheral edge of the aperture as shown.The under surface 19 of a protective cap 18 extends similarly over theperipheral edge of that aperture. The protective cap is provided with aninternal shape in general conformity with the contour of the sphericalball, having nominal, if any, clearance therefrom. With the cap being offlexible material and incorporating an annular recess, the cap can beinserted into the top plate normally. In use the cap can beself-aligning with the driven ball as the diameter of the recess of thecap is less than the aperture of the top plate so that shape and/ordimension imperfections during manufacture of the driven ball and/or theapertures in the top plate can be better tolerated in use.

The arrangement of protective cap 20 shown in FIG. 6 has similaroverlapping construction to the arrangement shown in FIG. 5 but isconstructed of metal. Thus it has an annular recess and an upper part 20extending over an upper peripheral part of the top plate defining theaperture and over a lower peripheral part thereof. The cap 20 can bemanufactured as a steel pressing or in the form of a steel plate havingthree or more spring clips welded or riveted thereto.

As shown in FIG. 7 the protective cap whether of resiliently flexible ormetal material may have a downwardly depending spigot 30 projectingthrough the aperture in the top plate 11. The spigot has acircumferential groove 31 below the top plate for receiving a retainingmember in the form of a circlip 32. Such preferred arrangement helpsprevent dislodgement of the protective cap in use and may control motionof the ball 10 more accurately.

We claim:
 1. A rolling ball deck apparatus having at least one rollingball assembly, each rolling ball assembly comprising a spherical ball,means for supporting the ball for free rotation about any horizontalaxis through the ball; a pair of horizontal drive shafts, one eitherside of the ball; a collar on each driving shaft and a periphery of eachcollar being in driving engagement with the ball at or close to ahorizontal plane through the equator of the ball, and between thehorizontal axis of the ball perpendicular to the drive shafts and thehorizontal axis parallel to the drive shafts whereby by rotating thedrive shafts the ball may be rotated about any horizontal axis.
 2. Anapparatus as claimed in claim 1 wherein the ball is supported by saidcollars and by a rolling bearing.
 3. An apparatus as claimed in claim 2wherein the rolling bearing comprises a rotatable ball disposed beneathsaid spherical ball and whose centre of rotation lies in a verticalplane generally equi-distant from the horizontal axes of said driveshafts.
 4. An apparatus as claimed in claim 1 including a base plateupon which said means for supporting said spherical ball is mounted andbrackets on said base plate for rotatably supporting said shafts.
 5. Anapparatus as claimed in claim 4 wherein said means for supporting saidspherical ball comprises a rolling ball bearing mounted upon an inclinedface of a flange which flange projects from said base plate.
 6. Anapparatus as claimed in claim 5 wherein said rolling bearing is springloaded to be capable of displacement in a vertical plane extendingthrough its centre of rotation, upon application of a load above apredetermined value to said spherical ball.
 7. An apparatus as claimedin claim 6 incorporating a stop member to limit depression of saidspherical ball when said spring loaded rolling bearing is displaced toovercome its spring loading.
 8. An apparatus as claimed in claim 1including an apertured cover plate positioned such that said sphericalball projects through an aperture to a distance above the surface ofsaid plate.
 9. An apparatus as claimed in claim 8 wherein at least oneaperture in said cover plate are provided with a ball cap having partswhich project both below and above said plate, and constructed to beself aligning with respect to said spherical ball in accommodating minortolerance deviations in said aperture and/or said spherical ball.
 10. Anapparatus as claimed in any preceding claim wherein the collars aregenerally plain cylindrical, corners thereof contacting the sphericalball in driving engagement.
 11. An apparatus as claimed in claim 10wherein the corners in driving engagement have a radius.
 12. Anapparatus as claimed in claim 1 wherein the collars have a conicalperiphery in driving engagement with said spherical ball.
 13. Anapparatus as claimed in claim 1 wherein a one-piece supporting block isused for mounting of said supporting means, said supporting block beingsecurely attached to a base plate.
 14. An apparatus as claimed in claim1 wherein the drive shafts extend to a series of side-by-side rollingball assemblies for simultaneously driving them.
 15. An apparatus asclaimed in claim 14 having multiple spherical balls and one or morepairs of drive shafts with an apertured cover plate through which saidspherical balls project, each drive shaft connected to a bi-directionaldrive mechanism.
 16. An apparatus as claimed in claim 15 wherein aseries of shafts are linked to the same drive mechanism.